The invention relates to a wing mirror having an electrically operable pivoting mechanism, and to an electrically operable pivoting actuator.
A pivoting actuator comprises two actuator parts rotatably mounted relative to each other. Furthermore, an electrically operable pivoting actuator comprises an electromotor and a transmission system for rotating those actuator parts relative to each other. A pivoting actuator can be used for various applications where it is desired to rotate or pivot two structural members relative to each other. For that purpose, one actuator part will be attached to one of these structural members, and the other actuator part will be attached to the other one of these structural members; when the actuator parts are then rotated relative to each other, operated electrically or non-electrically, the structural members will rotate or pivot relative to each other about a rotation or pivot axis coinciding with the rotation axis of the actuator parts. Within the scope of the present invention, the terms "rotate" and "pivot" will be used interchangeably.
Such a pivoting actuator can be used particularly but not exclusively in a wing mirror of a vehicle such as for instance a motorcar. Hence, the invention will hereinafter be described for such a practical example.
It is generally known that cars are fitted with at least one wing mirror. The wing mirror comprises a bowl-shaped mirror housing having disposed therein a mirror plate, which, during use, is directed substantially at right angles to the longitudinal direction of the car to enable the driver to view the road section located alongside and behind the car. The mirror housing projects over a particular distance from the side of the car. In particular situations, it is desired that that distance will be reduced, for instance during parking in a narrow space. For that purpose, the mirror housing can be pivoted relative to the car about a pivot axis which, in most cases, is directed substantially vertically, and the end of the mirror housing can be moved closer to the body of the car through a rearwardly directed rotational movement about that axis; such a movement will hereinafter be referred to as folding in, and the position thus reached will be referred to as fold-in position. The reverse pivotal movement, from the fold-in position to the normal operational position (also referred to as fold-out position) will be referred to as folding out.
This pivoting possibility also concerns a safety aspect. If an obstacle outside the car touches the mirror housing, the mirror housing yields, so that damage is avoided or at least reduced, both to the car and the mirror and to the obstacle, which may also be a person. Hence, for reasons of safety, it is desired, and often even laid down by law, that the mirror housing is capable of making a comparable pivotal movement in forward direction. Hereinafter, such a movement will be referred to as folding over, and the position thus reached will be referred to as fold-over position. The reverse pivotal movement, from the fold-over position to the normal operational position, will be referred to as folding back.
To enable those pivotal movements, the mirror housing is pivotably mounted on a mirror foot or mirror base, intended to be fixedly mounted on the car. These pivotal movements can then be carried out under the influence of an external force, which will be referred to as manual operation. From a viewpoint of control convenience, the wing mirror further comprises a pivoting actuator or pivoting mechanism which can be electrically controlled by the driver of the car, i.e. for instance by pressing a button, for carrying out this fold-in movement and this fold-out movement. The pivoting mechanism comprises an electromotor and a transmission mechanism coupled to the mirror housing and the mirror foot. The pivoting mechanism is designed so that it is not only able to carry out the fold-in movement and the fold-out movement through excitation of the electromotor, but also to permit all these pivotal movements during the action of an external force without damaging the motor and/or transmission mechanism.
Pivoting actuators having the properties described hereinabove are now generally known. An example thereof is for instance described in German patent specification 4,023,375. In this known construction, two grooves are concentrically provided in a housing part of the driving gear, of which the first groove has a smaller length than the second groove. Provided diametrically opposite the first groove is a third groove having the same length as the first groove. The mirror foot has a stop cam engaging the second groove of greater length. When a pivotal movement of the mirror housing relative to the mirror foot is carried out, this stop cam moves through the second groove; the ends of the second groove form a stop for this stop cam, and thus define the extreme fold-in position and the extreme fold-over position of the wing mirror. The mirror foot further comprises a cam disc which under normal conditions couples the mirror foot to the central axis by means of noses engaging recesses fixed relative to the mirror foot. This cam disc comprises two stop cams which engage the first and third grooves respectively of the housing part of the driving gear. Under normal conditions, these two stop cams will move through the first and third grooves of the housing part during a pivotal movement between the fold-in position and the fold-out position. One end of the first groove forms a stop for the stop cam running therein, just as one end of the third groove forms a stop for the stop cam running therein, which stops define the fold-out position of the wing mirror.
The construction described in this publication is hence rather complicated, and comprises relatively many components.
For carrying out a fold-over movement from the fold-out position, it is necessary that the coupling between the cam disc and the mirror foot be removed. For that purpose, the noses of the cam disc leave the recesses. The folding back of a mirror housing from the fold-over position to the normal operational position should then be carried out manually, which is regarded as a drawback. If in the fold-over position the electromotor is excited, the mechanism can under certain conditions find a "normal" position which does not correspond to the fold-out position intended.
Further, it is a drawback of the known construction that the component having grooves is not symmetrical, so that the known pivoting mechanism can only be used for a left mirror or for a right mirror. In other words, for a left mirror and for a right mirror, two mutually different pivoting mechanisms should be provided, which is relatively expensive.